| Author | Navaneethan, Navaratnam. |
| Call Number | AIT Thesis no.EV-07-27 |
| Subject(s) | Sewage--Purification--Activated sludge process
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| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Environmental Engineering and Management. |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. EV-07-27 |
| Abstract | Ultrasonication of waste activated sludge is usually applied in the enhancement of sludge solubilization and sludge disintegration. This research examines the effectiveness of ultrasound pretreatment on waste activated sludge (WAS) disintegration at different specific energies and sonication durations in the anaerobic digestibility of control, full stream and part stream (50% sonicated + 50% nonsonicated sludge) sonicated WAS. A specific energy of 12 kWs/gTS was the maximum specific energy for the effective disintegration of WAS. The mesophilic digester was operated with SRTs of 20 and 15 days. The ultrasonic pretreatment enhanced the subsequent anaerobic digestibility resulting better removal of TS and VS. The biogas production rate in the full Stream and part stream digesters was increased by 102% and 91% respectively, for a SRT of 20 days in comparison to the control digester, whereas at an SRT of 15 days, the biogas production rate was increased in the full stream and part stream digesters by 81.4% and 57.1 respectively. Although, the specific biogas production was the same in full stream and part stream digesters for both SRTs, which is 0.500 L/g VS removed in a SRT of 20 days and 0.64 L/g VS removed in a SRT of 15 days respectively. The dewaterabilty of the sludge was ranked in the ascending order as full stream, part stream, control digester sludge and raw sludge. Based on the energy balance, energy gained from biogas in the full stream is around two folds compared to energy gained from biogas from control digester. In part stream digester, around 88% of sonication energy input can be replenished in the form of biogas energy. The ultrasonic pretreatment improved the VS hydrolysis coefficient in the full and part stream digesters for both SRTs. |
| Year | 2007 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. EV-07-27 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Environmental Engineering (EV) |
| Chairperson(s) | Visvanathan, C.; |
| Examination Committee(s) | Chongrak Polprasert;Annachhatre, Ajit P.;Khanal, Samir Kumar; |
| Scholarship Donor(s) | THAILAND (HM Queen); |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2007 |